33	As	Arsenic
Atomic Weight: 74.92159				Shells: 2,8,18,5
Group: Non-Metal				Filling orbital: 4p3
Crystal Structure: Rhombohedral				Covalent radius: 1.20 Å
Oxidation States: +3,+5,-3				Atomic radius: 1.33 Å
Electronegativity, Pauling: 2.18				Atomic volume: 13.1 cm³/mol
State at RT: Solid				First ionization potential: 9.81 V
Melting Point: 1090°K				2nd ionization potential: 18.633 V
Boiling Point: 889°K (sublimes)				3rd ionization potential: 28.351 V
Density @ 293°K: 5.72 g/cm³				Specific heat: 0.33 J/gK
Electrical conductivity: 0.0345 106/cm ohm				Heat of vaporization: 34.760 kJ/mol
Thermal conductivity: 0.500 W/cmK				Heat of fusion: ?
Element Nuclides
Nuclide		Abundance	Weight	Spin	Half-Life	Decay Modes
As71		0.%	71.	2.5	2.72d	, +
As72		0.%	72.	2	26.0h	+,
As73		0.%	73.	1.5	80.3d
As74		0.%	73.924	2	17.78d	, +, -
As75		100.%	74.9216	1.5		Stable
As76		0.%	75.922	2	26.3h	-
As77		0.%	76.921	1.5	38.8h	-
As79		0.%	79.	-1.5	9.0m	-

Name origin: Greek: arsenikos (male); Latin: arsenicum.
Description: Gray brittle non-metal flakes.
Discovered by: ?
Year: ?
Location: ?
Sources: Found in mispickel (arsenopyrite).
Uses: It is a deadly poison. Conducts electricity. Used in semiconductors.

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Registry Numbers

• CAS: 7740-38-2
• RTECS: CG0525000
• DOT: 1557
• NFPA ratings (1-4)
  • Health: 3
  • Flammability: 2

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Description
appearance and odor may vary

Incompatabilities
halogenated compounds rhubidium carbide

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From DOT guide book, Guide Number 53,

Fire or Explosion Hazards
Some of these materials may burn but do not ignite readily.

Health Hazards
Poison. Poisonous if swallowed. Inhalation of dust poisonous. Fire may
produce irritating or poisonous gases. Runoff from fire control or
dilution water may cause pollution.

Emergency Action: General
Keep unnecessary people away. Stay upwind; keep out of low areas.
Isolate hazard area and deny entry.
Wear self-contained breathing apparatus and full protective clothing.
Also, in case of water pollution call local authorities.
FOR EMERGENCY ASSISTANCE CALL CHEMTREC (800) 424-9300

Emergency Action: Fire
SMALL FIRES: Dry chemical, CO2, water spray or foam.
LARGE FIRES: Water spray, fog or foam.
Move container from fire area if you can do it without risk.

Emergency Action: Spill or Leak
Do not touch spilled material. Stop leak if you can do it without risk.
SMALL SPILLS: Take up with sand, or other non-combustible absorbent material,
then flush area with water.
SMALL DRY SPILLS: Shovel into dry containers and cover; move containers;
then flush area with water.
LARGE SPILLS: Dike far ahead of spill for later disposal.

Emergency Action: First Aid
Move victim to fresh air: call emergency medical care.
Remove and isolate contaminated clothing and shoes.
In case of contact with material, immediately flush skin or eyes with running
water for at least 15 minutes.

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Material Safety Data Sheet (MSDS)
Still More Information

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